While Donald Trump refuses to condemn white supremacy, the Proud Boys are gleefully standing by. Last night’s presidential debate offered a jarring example of the president’s penchant for inciting right-wing extremist groups when he couldn’t bring himself to denounce his followers who stoke hate and violence. Instead, Trump offered a near-explicit call to arms: “Proud Boys, stand back and stand by.”

Now many are asking, “Who are the Proud Boys?” As Keith explains, the group was formed by former Vice co-founder Gavin McInnes in 2016, and there’s a strong thread of racism, misogyny, and violence running through its identity. The Proud Boys actively…